1. Field of the Invention
This invention relates generally to nozzle apparatus, and more particularly to a nozzle apparatus for cleaning applications, which is rapidly convertible between spray and foam forming modes of operation.
2. Description of the Prior Art
Industrial cleaning apparatus has traditionally employed the principle of directing high pressure spray of relatively dilute detergent solutions against the article to be cleaned, thus relying upon the hydraulic cleansing action of the spray. In several applications, such as in conveyor type spray washers (e.g. dishwashers, hydro-bottle washers etc.) the production of foam during the cleaning operation is generally undesirable and defoaming agents are typically used to minimize foam formation. In other applications such as in the cleaning of carpets and upholstery it has been found that foam cleansers used in combination with brushing/scrubbing action are effective to suspend the soil removed from the carpet or upholstery in the foam. When the foam is allowed to dry, the foam/soil residue can be simply vacuumed away. In such applications, the foaming agent is desirably of a type which will dry to a powder so that it can be completely removed when dry.
The use of foam in cleaning food handling equipment and other industrial hard surface applications, however, is relatively new in the art. It has now been found that in certain industrial cleaning applications particularly in those requiring the cleaning of large surfaces or hard to reach geometrical configurations, it is desirable to use a non-drying foam cleansing agent which will cling to the surface to be cleaned for extended periods of time, prolonging the contact between the soil and detergent within the foam for solvation, hydration or emulsification of the soil. In many applications, foam cleansing techniques can be significantly more efficient and less expensive to use than the prior art high pressure hydraulic cleansing techniques. With the use of hydraulic cleansing techniques, large volumes of relatively dilute detergent solutions are directed at high pressure against the object to be cleansed. With such techniques, the cleansing of stubborn soil requires the hydraulic spray to be directed at a specific area for extended periods of time, prolonging the cleansing operation. Further, with use of conventional high pressure cleaning operations, the high pressure spray nozzle must typically be held within a foot of the surface to be cleaned to provide effective hydraulic cleansing action.
The use of foam cleansing techniques for hard surfaces overcomes the aforementioned disadvantages of hydraulic cleansing techniques. When cleaning with foam, which is highly visible to the operator, the operator knows exactly what areas have been exposed to the cleaner thus insuring against missed areas. Likewise, the adequacy of rinsing is visually detectable, enabling an operator to completely rinse off any residues of cleansing solution from the object being cleaned. Since the foam clings to vertical and overhead surfaces, such surfaces are particularly adapted for cleansing by this technique. Further, since the cleansing action is minimally dependent on any hydraulic action, the "reach" of a foam producing nozzle can be extended outwardly from 10 to 20 feet making it possible to clean relatively remote areas without the need for the operator's physical presence directly adjacent the object to be cleaned. Foam cleaning enables significant time to be saved in the cleansing of larger articles since an operator can start with foam applications from one end of the article to be cleaned, work his way to the far end, and simply return to his starting point and begin rinsing operations. No wasted time for prolonged spraying efforts in any one area to remove stubborn soil is required. Also, since the same volume of detergent solution may clean a significantly greater area with the foam generating operations as compared to high-pressure spray producing applications, the detergent concentration level within the foam can be significantly increased to insure high cleansing action thereby, in a highly economical manner.
Prior art cleansing apparatus has conventionally been designed to accommodate a fixed type of nozzle designed either to eject high-pressure spray solutions for hydraulic cleansing action or to produce and to eject a foam-type cleanser. The foam producing nozzles have been provided with various tips which may be secured to the ejection port of the nozzle to vary the foam ejection pattern emitted therefrom. It is highly desirable for an operator to use the same nozzle for directing cleansing foam against the object to be cleaned and for directing a rinse solution for removing the foam from the object. However, the prior art is void of any such nozzle apparatus.
Foam producing nozzle configurations have also appeared for use in applications other than for cleansing. The largest use of such nozzles has been in the fire extinguishing art and in the distribution of herbicides and insecticides. As in the cleansing art, however, such nozzles have been designed for a single purpose use of producing either foam or pressurized sprays.
The present invention overcomes the above-mentioned shortcomings of the prior art nozzle structures for use with pressurized spray and/or foam producing cleansing apparatus. The present invention provides a highly versatile hand-held nozzle apparatus which is usable with a detergent solution source for enabling an operator to selectively direct against the target area either a pressurized spray for hydraulic cleansing or rinsing action, or a dry (stiff) foam for foam cleansing action. The nozzle apparatus of this invention is rapidly convertible between its pressurized spray and its foam producing modes, filling a long-felt need for such a device in the art.